, Volume 27, Issue 4, pp 959–971

Drought-induced adaptive changes in the seedling anatomy of Acacia ehrenbergiana and Acacia tortilis subsp. raddiana

  • Ibrahim M. Aref
  • Abdallah I. Ahmed
  • Pervaiz R. Khan
  • Hashim A. El-Atta
  • Muhammad Iqbal
Original Paper

DOI: 10.1007/s00468-013-0848-2

Cite this article as:
Aref, I.M., Ahmed, A.I., Khan, P.R. et al. Trees (2013) 27: 959. doi:10.1007/s00468-013-0848-2


This study, conducted on Acacia species (Acaciaehrenbergiana Hayne and Acacia tortilis subsp. raddiana (Savi) Brenan) to determine their adaptive capacity to tolerate drought and suitability for reforestation, revealed that leaf water potential (ψ) decreased in both the species with increase in drought intensity. With increase in the intensity of drought, vessel diameter increased in A. ehrenbergiana, causing a significant decline in vessel frequency mm−2 of the transverse wood surface, while it decreased in A. tortilis, leading to a crowded vessel population. Vessel-wall thickness, in conjunction with inter-vessel pit membrane thickness, showed a positive correlation with drought stress in both the species. Ray dimensions generally decreased in A. ehrenbergiana but increased in A. tortilis under increasing degree of drought. The transverse fiber-wall area decreased in A. ehrenbergiana, thus lowering the density (r = 0.996) and enhancing the vulnerability of wood (r = −0.979) under the drought stress, but increased in A. tortilis, causing a high density (r = −0.979) and low vulnerability of wood (r = 0.869), under the same set of conditions. Correlation of wood density with vulnerability index was stronger in A. ehrenbergiana (r = −0.993) than in A. tortilis (r = −0.753). Diameters and thickness of inter-vessel pit membrane were linearly correlated with increasing intensity of drought in both the species, but its area fraction per vessel segment increased due to water stress in A. ehrenbergiana and decreased in A. tortilis. This study indicated that, on the whole, A. tortilis has a greater capacity to tolerate the harshness of drought than A. ehrenbergiana.


Drought toleranceInter-vessel pit membraneSaudi Arabian treesVessel morphologyXylem vulnerability



Formalin–acetic acid–alcohol


Field capacity


Hydraulic conductivity per xylem cross-sectional area


Mean cavitation pressure


Moderate deficit irrigation


Radial longitudinal section


Relative water content


Severe deficit irrigation


Tangential longitudinal section


Vulnerability factor


Vessel-lumen diameter


Vessel-wall thickness

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Ibrahim M. Aref
    • 1
  • Abdallah I. Ahmed
    • 1
  • Pervaiz R. Khan
    • 1
  • Hashim A. El-Atta
    • 1
  • Muhammad Iqbal
    • 2
  1. 1.Plant Production Department, College of Food and Agricultural SciencesKing Saud UniversityRiyadhSaudi Arabia
  2. 2.Department of Botany, Faculty of ScienceHamdard UniversityTughlaqabadIndia